3-(2-Methylphenyl)-3a,4-dihydro-3H-chromeno[4,3-c]isoxazole-3a-carbonitrile

In the title compound, C18H14N2O2, the pyran ring of the chromeno ring system has a half-chair conformation, and the dihedral angle between its mean plane and the benzene ring is 5.3 (2)°. The isoxazole ring forms a dihedral angle of 74.6 (2)° with the attached benzene ring and is inclined to the mean plane of the chromeno ring system by 15.06 (19)°. In the crystal, there are no significant intermolecular interactions.

In the title compound, C 18 H 14 N 2 O 2 , the pyran ring of the chromeno ring system has a half-chair conformation, and the dihedral angle between its mean plane and the benzene ring is 5.3 (2) . The isoxazole ring forms a dihedral angle of 74.6 (2) with the attached benzene ring and is inclined to the mean plane of the chromeno ring system by 15.06 (19) . In the crystal, there are no significant intermolecular interactions.
The molecular structure of the title molecule is illustrated in Fig. 1. In the chromeno ring system, the dihedral angle between the mean plane of the pyran ring, which has a half-chair conformation, and the benzene ring is 5.3 (2)°. The dihedral angle between the mean plane of the chromeno ring system and isoxazole ring is 15.06 (19)°. The isoxazole ring also forms a dihedral angle of 74.6 (2)° with the the benzene ring (C11-C16). The geometric parameters of the title molecule agree well with those reported for closely related structures (Gangadharan et al., 2011;Swaminathan et al., 2011).
In the crystal, there are no significant intermolecular interactions.

Experimental
NCS (4 mmol) was added pinch wise over 3h to a solution of (E)-2-((2-((E)-(hydroxyimino)methyl)phenoxy)methyl)-3o-tolylacrylonitrile(2 mmol) in CCl 4 at 273 -283 K. After Et 3 N (4 mmol) was added to the reaction mixture which was stirred at room temperature for 2 h. After completion of the reaction, the mixture was evaporated under reduced pressure and the resulting crude mass was diluted with water (15 ml) and extracted with ethyl acetate (3 × 15 ml). The combined organic layers washed with brine (2 × 10 ml) and dried over anhydrous Na 2 SO 4 . The organic layer was evaporated and purified by column chromatography (silica gel 60-120 mesh; 7% EtOAc in hexanes) to provide the desired title product as a colourless solid. Crystals suitable for X-ray diffraction were obtained by slow evaporation of a solution of the title compound in ethyl acetate at room temperature.

Refinement
All the hydrogen atoms were placed in calculated positions and refined as riding atoms: C-H = 0.93-0.98 Å with U iso (H) = 1.5U eq (C) for methyl group and = 1.2U eq (C) for other groups. In the final cycles of refinement, in the absence of significant anomalous scattering effects, Friedel pairs were merged and Δf " set to zero.  The molecular structure of the title compound, with the atom labeling. Displacement ellipsoids are drawn at the 30% probability level. Special details Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes. Refinement. Refinement of F 2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F 2 , conventional R-factors R are based on F, with F set to zero for negative F 2 . The threshold expression of F 2 > σ(F 2 ) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F 2 are statistically about twice as large as those based on F, and R-factors based on ALL data will be even larger.